The present invention relates to power take-off (PTO) mounting arrangements and, more particularly, to PTO systems having isolation mounting.
Front mount (FM) mowers have become increasingly popular within some areas of application because of their superior visibility and maneuverability, and relative stability. An FM mower is conventionally a front wheel drive rear wheel steer vehicle and includes a front hitch or mount for the attachment of implements, such as a mower deck or snow blower. In order to deliver power to an attached implement, it is known to equip the FM mower with a PTO system which selectively communicated with the engine of the FM mower.
Because of the very short length and low ground clearance of an FM mower, many of the conventional PTO systems are ill-suited for application in FM mowers. Further, the use of a diesel and other engines which exhibit a high torque displacement and vibration presents special consideration which impacts on the characteristics of a suitable PTO system. Diesel and similar engines due to the higher torque displacement and vibration require that diesel and similar characteristic engines be isolation-mounted to the mower frame. In contrast, engines which exhibit substantially less torque displacement and vibration, if desired, may be hard-mounted to the mower frame without substantial consequence.
It is further a consideration when employing diesel and similar engines in an FM mower that the PTO system not cause substantial counter loading of the engine crankshaft or crankshaft bearings which could precipitate engine crankshaft misalignment or premature crankshaft bearing failure. In addition, a PTO system, which is driven off the crankshaft through an engine torque shaft, may provide a counter resistance to engine torque deflection, for example, where the PTO system is hard-mounted to the vehicle frame and is driven from the torque shaft through a fixed length median such as a continuous belt. The counter resistance caused by the belt during engine torque displacement imparts a crankshaft torque about the crankshaft bearing which may result in engine misalignment. A still further consideration is that the PTO system not unduly load the torque shaft between the engine and transaxle. In the FM mower, the engine and the transaxle are in relative close proximity with communication therebetween being provided by a torque shaft. Because of this short distance, load responsive deflection or bending of the torque shaft precipitated by the PTO system cannot easily and cost effectively be accommodated by a hard-mounted PTO system.